NOTHING ruins a scene faster, I think, than a constant asking of "are you okay?" It takes a sub/slave/bottom out of the head space quite quickly; it may, in fact, make the sub/slave/bottom lose confidence in the Top's ability to "read" the scene and keep it alive and on edge.
Still, there are times when it doesn't hurt to make sure that all is okay, that there is no "bad" pain, that the panic-breathing is because the sub is loving every minute rather than truly panicking, etc.
Out of the blue yesterday, working with a young man who clearly was not very experienced and was, in my opinion, a little overly excited and maybe even close to passing out from hyperventilation, and occasionally shivering from fear? or excitement?--in any case, out popped these words from me---
"Are you where you wanna be?"
When the scene was over I had used the phrase three times, each time making direct verbal contact with the young man, but I believe never destroying the critical head-space we were working so hard to achieve. The phrase carries so many meanings and allows for so many interpretations on the sub's part, that it was, for me, a way to check in, without breaking the focus.
The sub answered "yes Sir" all three times and on we went.....
And each time the answer seemed to say:
"Yes, i like this headspace."
"Yes, i'm glad i hooked up with You."
"Yes, this bondage is great and comfortable and unforgiving."
"Yes, i love wearing hoods."
"Yes, this is the punishment i craved."
"Yes, and I never want to leave."
And yes, I'm officially working on a "Rosetta Stone" language class for interpreting "yes Sir" and "mmmmmphfyps", just for dedicated leather/rubber/BDSM men.